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Eggs are a most common chicken product on
the market. They are a way chicken hatches. Eggs are commonly eaten
in many cultures and are important staples of the economy. There
are huge commercial farms for egg production. That why there
is a whole field of science devoted to eggs. No, it is not called
eggology. The study of eggs is called oology. It comes from Greek
word "ovum " which means eggs.
Birds lay eggs. In chicken, hen lays eggs
about 24 hours after fertilization. Eggs produced by chicken are
oval shape and smooth. The shell color varies in different breeds.
Eggs can be white, or many shades of beige. Egg shell has thousands
of pores or small openings. They allow a chick inside to breathe.
Hens can lay an egg every 24 hours. An interesting fact is that hen
will lay an egg only during daylight!
LOOK
INSIDE THE CHICKEN EGG:
Roll your mouse over the egg to learn
about the parts:
PARTS OF AN EGG:
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OUTER
MEMBRANE
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First
membrane inside the shell. Its job is to keep dangerous thing, like
bacteria out of the egg.
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INNER
MEMBRANE
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Second
membrane. Its job is also to prevent dangerous things from entering
the egg.
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ALBUMEN
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Albumen is a fancy name for egg white. Egg
white is made of protein. An embryo develops here. Albumen provides
protein that embryo needs to grow correctly.
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SHELL
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Shell
is on outside the egg. Its job is to protect the insides. Shell has
a lots of calcium and many tiny pores. Pores allow the air in and
out of the egg. Did you know that the older the hen, the thinner
the shell?
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CHALAZEA
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You
may have seen chalazae. They are little strings in the egg
white. If you ever saw them you may have thought these are part of
an embryo, but they are not. Chalazae are part of an egg white that
keeps yolk in the center of the egg white.
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YOLK
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Yolk
has many nutrients. It is a yellow part in the center of an egg. It
is held in the center by the chalazae. It provides nutrition for
the embryo. In the yolk there is also a germinal disc. This is a
part where fertilization happens.
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VITTELINE MEMBRANE
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This
membrane is also called yolk membrane and it surrounds the yolk of
an egg. This membrane makes sure that yolk and egg white do not
mix. This is called mottling. Mottling does not make egg bad to
eat, but it makes it different when you see it. It has blotches and
different colors.
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AIR CELL
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Air
cell is very important. First of all it helps egg stay in one piece
because it absorbs the shock. In addition, air cell will help a
baby breathe. When the chick starts poking the egg to get out, air
cell will provide first air so that it can breathe on its
own.
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